CN100594368C

CN100594368C - Material high-speed stretch tester and test methods thereof

Info

Publication number: CN100594368C
Application number: CN200710156357A
Authority: CN
Inventors: 陈大年; 胡金伟; 王焕然; 金扬辉
Original assignee: Ningbo University
Current assignee: Ningbo University
Priority date: 2007-10-22
Filing date: 2007-10-22
Publication date: 2010-03-17
Anticipated expiration: 2027-10-22
Also published as: CN101158625A

Abstract

The invention discloses a device for material high-speed stretch test, which is characterized by including a gaseous gun tube for shooting pill at high speed. And the outlet of the gaseous gun tube isfixedly provided with a foundation bed, and the foundation bed is provided with a central hole coaxial with the gaseous gun tube, wherein, at least three test piece fixing holes are evenly distributed around the central hole on the head face of the foundation bed; and the axes of the test piece fixing holes are parallel with the axes of the central hole; a sleeve is coaxially and fixedly arrangedwithin the central hole; a flat target plate fixedly connected with a test piece is vertically arranged at the other end of the sleeve; a 1st speed measuring electric probe for measuring the pill speed is arranged at the side wall of the sleeve; and a 2nd speed measuring electric probe for measuring the stretching speed of the test piece is arranged at the outer side of the flat target plate. Theinvention has the advantage of giving full play to the capacity of gaseous gun tube driving the pill at high speed, pulling a plurality of stretching test pieces by the impact of pills to the flat target plate, and satisfies the requirements for precise determination of critical impact stretching speed of various materials under random factors.

Description

A kind of material high-speed stretch tester and test method thereof

Technical field

The present invention relates to a kind of material high-speed stretch tester and test method thereof that is used to measure material critical tensile impact speed.

Background technology

Because the extension characteristics the when extension characteristics of metal material when high-speed stretch is better than the quasistatic stretching, so the high-speed molding technology of hardware is used more and more widely at mechanical field.Yet when draw speed surpassed certain critical value, extension characteristics can descend suddenly, and this critical value is called as the critical impulse draw speed of material, and its theoretical value is ended corresponding with the plastic wave of material.The test unit that can be used for research material critical impulse draw speed abroad is to come the tensile impact test specimen by the high energy rate forging hammer that is driven by flywheel, this device is set up by U.S. Watertown Arsenal laboratory the earliest, but this device finds that in test the tensile impact speed and the measuring accuracy thereof that can obtain are all not high, therefore can't obtain material critical tensile impact speed accurately.In addition, owing to lack effectively both at home and abroad at present and material critical tensile impact speed trial device and relevant theoretical research efficiently, therefore the critical impulse draw speed data of various metal materials are more rare.

Summary of the invention

Technical matters to be solved by this invention provides a kind of material high-speed stretch tester and test method thereof, in order to the critical impulse draw speed of the various materials of accurate mensuration.

The present invention solves the problems of the technologies described above the technical scheme that is adopted: a kind of material high-speed stretch tester, it comprises sleeve and is used for the gas gun tube of transmitted at high speed bullet, the exit of described gas gun tube is set with pedestal, described pedestal is provided with and the coaxial center pit of described gas gun tube, be provided with at least three equally distributed test specimen fixed orifices around described center pit on the end face of described pedestal, the axis of described test specimen fixed orifice and the parallel axes of described center pit, one end of described sleeve is coaxial to be fixedly installed in the described center pit, the other end of described sleeve is vertically installed with the plane target plank of fixedlying connected with test specimen, the sidewall of described sleeve is provided with and is used to measure first of the velocity of shot electric probe that tests the speed, and the arranged outside of described plane target plank is useful on measures second of the test specimen draw speed electric probe that tests the speed.

Described test specimen fixed orifice is a threaded hole, described plane target plank is provided with and the coaxial corresponding through hole of described threaded hole, the outer face of described plane target plank is provided with the fixed block that is threaded with test specimen, and described second electric probe that tests the speed is arranged on the outside of described fixed block.

Described first electric probe and described second electric probe that tests the speed that tests the speed is the high precision speed-measuring electric probe, and described first test the speed electric probe and described second output terminal that tests the speed electric probe all is connected with network signal source, time interval measuring instrucment and high performance oscillograph.

The material of described pedestal, described sleeve, described plane target plank and described fixed block is plow-steel.

A kind of test method of using described material high-speed stretch tester, it may further comprise the steps:

(1), the end with test specimen is connected with described test specimen fixed orifice, the other end of test specimen passes the through hole on the described plane target plank and is connected with fixed block, between the main body of the two ends of test specimen and test specimen, zone of transition is set, and the length-diameter ratio that makes the test specimen main body is greater than 13;

(2), second electric probe that tests the speed is installed in the outside of described fixed block;

(3), from the gas big gun emission bullet parallel impact plane target plank, test specimen is stretched fast, obtain the material impact draw speed value of test specimen by being installed in second of the described fixed block outside electric probe that tests the speed;

(4), regulate the speed of bullet impact plane target plank, repeat above-mentioned steps again, rupture near the end and the other parts of test specimen when not having distortion when test specimen is being hit to stretch, the material impact draw speed value of the test specimen of acquisition is the critical value of tensile impact speed.

Compared with prior art, the invention has the advantages that the ability of giving full play to gas big gun high-speed driving bullet, by many tensile test specimens of bullet impact plane target plank traction, the critical impulse draw speed that can satisfy the various materials of research requires (the tens of rice of per second are to hundreds of rice), because of high-precision second electric probe that tests the speed is arranged in the arranged outside of fixed block, can accurately record the test specimen speed of end of stretching that is hit; When tensile impact speed hour, tensile test specimen deforms near stiff end, constriction and fracture; When tensile impact speed increases, the constriction of test specimen and fracture position leave stiff end gradually, when tensile impact speed reaches certain critical value, test specimen ruptures near the stretching end that is hit, the other parts of test specimen almost do not have distortion, and this critical velocity is the critical impulse draw speed experiment value of this material for test; For the test specimen of same material, because can there be certain critical impulse draw speed difference in enchancement factor, adopt this device under same tensile impact condition, to carry out tension test to many test specimens of same material, take into account the critical impulse draw speed of enchancement factor with acquisition, and the contrast test that can under same tensile impact load, stretch to the test specimen of different materials.

Description of drawings

Fig. 1 is the structural representation of the present invention in conjunction with test specimen.

Embodiment

Embodiment describes in further detail the present invention below in conjunction with accompanying drawing.

As shown in the figure, a kind of material high-speed stretch tester, it comprises sleeve 5 and is used for the gas gun tube 2 of transmitted at high speed bullet 1, the exit of gas gun tube 2 is set with pedestal 3, pedestal 3 is provided with the center pit 31 coaxial with gas gun tube 2, one end of sleeve 5 is coaxial to be fixedly installed in the center pit 31, the other end of sleeve 5 is vertically installed with plane target plank 8, be provided with three equally distributed threaded holes 32 around center pit 31 on the end face of pedestal 3, the parallel axes of the axis of threaded hole 32 and center pit 31, plane target plank 8 is provided with and threaded hole 32 coaxial corresponding through holes 81, the outer face of plane target plank 8 is provided with the fixed block 9 that is threaded with test specimen 6, the sidewall of sleeve 5 is provided with and is used to measure high-precision first of the bullet 1 speed electric probe 10 that tests the speed, the arranged outside of fixed block 9 is useful on measures high-precision second of the test specimen draw speed electric probe 7 that tests the speed, first the test the speed output terminal of electric probe 7 of electric probe 10 and second that tests the speed all is connected with network signal source (not shown), time interval measuring instrucment (not shown) and high performance oscillograph (not shown), pedestal 3, sleeve 5, the material of plane target plank 8 and fixed block 9 is plow-steel.

A kind of test method of using above-mentioned test unit, it may further comprise the steps:

(1), an end of test specimen 6 is connected with threaded hole 32, the other end of test specimen 6 passes the through hole 81 on the plane target plank 8 and is connected with fixed block 9, between the main body of the two ends of test specimen 6 and test specimen 6 zone of transition 61 is set, and the length-diameter ratio that makes test specimen 6 main bodys is greater than 13;

(2), second electric probe 7 that tests the speed is installed in the outside of fixed block 9;

(3), from the gas big gun emission bullet 1 parallel impact plane target plank 8, test specimen 6 is stretched fast, obtain the material impact draw speed value of test specimens 6 by being installed in second of fixed block 9 outsides electric probe 7 that tests the speed;

(4), regulate the speed that bullet 1 impacts plane target plank 8, repeat above-mentioned steps again, rupture near the end and the other parts of test specimen when not having distortion when test specimen 6 is being hit to stretch, the material impact draw speed value of the test specimen 6 of acquisition is the critical value of tensile impact speed.

Claims

1. A material high-speed tensile test device, characterized in that it includes a sleeve and a gas gun barrel for high-speed projectile launch, the outlet of the gas gun barrel is fixedly provided with a base, and the base is fixed A central hole coaxial with the gas gun barrel is provided, and at least three uniformly distributed sample fixing holes are arranged around the central hole on the end surface of the base, and the test piece fixing holes are The axis is parallel to the axis of the central hole, one end of the sleeve is coaxially fixed in the central hole, and the other end of the sleeve is vertically provided with a plane target plate fixedly connected with the test piece , the side wall of the sleeve is provided with a first velocity-measuring electrical probe for measuring the velocity of the projectile, and the outer side of the planar target plate is provided with a second velocity-measuring electrical probe for measuring the tensile velocity of the test piece.

2. A high-speed tensile test device for materials as claimed in claim 1, characterized in that the fixing hole of the test piece is a threaded hole, and the flat target plate is provided with a threaded hole coaxially corresponding to the threaded hole. through holes, the outer end surface of the planar target plate is provided with a fixing block screwed with the test piece, and the second speed measuring electric probe is arranged on the outside of the fixing block.

3. A material high-speed tensile test device as claimed in claim 1, characterized in that said first speed-measuring electric probe and said second speed-measuring electric probe are high-precision speed-measuring electric probes, so The output terminals of the first speed-measuring electric probe and the second speed-measuring electric probe are connected with a network signal source, a time interval measuring instrument and a high-performance oscilloscope.

4. A material high-speed tensile testing device as claimed in claim 2, characterized in that the materials of the base, the sleeve, the planar target plate and the fixing block are all high strength steel.

5. A test method using the material high-speed tensile test device according to claim 1, characterized in that it comprises the following steps:

(1), one end of the test piece is connected with the described test piece fixing hole, the other end of the test piece passes through the through hole on the described plane target plate and is connected with the fixed block, and the two ends of the test piece are connected with the test piece Set a transition zone between the main bodies of the test piece, and make the length-to-diameter ratio of the main body of the test piece greater than 13;

(2), the second speed measuring electric probe is installed on the outside of described fixed block;

(3), projectiles are launched from the gas cannon to impact the flat target plate in parallel, so that the test piece is stretched rapidly, and the material impact tensile velocity of the test piece is obtained by the second speed measuring electric probe installed on the outside of the fixed block value;

(4), adjust the velocity of the projectile impacting the flat target plate, and then repeat the above steps, when the test piece is broken near the impact tensile end and other parts of the test piece are not deformed, the material impact tensile velocity value of the obtained test piece That is, the critical value of impact tensile velocity.